The papillary muscle sling for ischemic mitral regurgitation

Late outcome of coronary artery bypass grafting with or without mitral repair for moderate or moderate-severe ischemic mitral regurgitation

BACKGROUND

Operative indication of the additional mitral repair for moderate ischemic mitral regurgitation (MR) in the setting of coronary artery bypass grafting (CABG) is still unclear.

METHODS

This study was designed as the nation-wide multi-center retrospective analysis with additional survival data. CABGs without past heart surgery registered in 2014 and 2015 were included. Concomitant surgery other than tricuspid or arrhythmia surgery, mitral replacement, and off-pump cases, was excluded. Grade 1 or 4 MR, and ejection fraction < 20 or > 50 were excluded. Additional questionnaire was sent to each hospital, regarding the pathology of MR and clinical outcomes. Additional data were registered between May 28, 2021 and Dec 31, 2021, and the primary outcomes were all-death and cardiac death. The secondary outcomes were heart failure and cerebrovascular event requiring admission, mitral re-intervention. Patients underwent on-pump CABG (CABG only group 221 cases) and CABG with mitral repair (CABG + Mitral repair group 276 cases) were enrolled.

RESULTS

After Propensity score matching, 362 cases (CABG only 181cases vs CABG + mitral repair 181 cases) were matched. Cox regression model showed no statistical difference in the long-term survival between CABG alone group and combined procedure group (p = 0.52). Cardiac death (p = 1.00), heart failure (p = 0.68), and cerebrovascular event (p - 0.80) requiring admission were not different between groups as well. The incidence of mitral re-intervention was very few (2 cases in CABG only group, 4 cases in CABG + mitral repair group).

CONCLUSIONS

In patients with moderate ischemic MR, additional mitral repair to CABG did not improve long-term survival, freedom from heart failure, or cerebrovascular event.

Impact of Mitral Regurgitation Recurrence on Mitral Valve Repair for Secondary Ischemic Mitral Regurgitation

OBJECTIVES

The current guidelines still do not include specific recommendations on the use of subvalvular repair (SV-r) for treatment of ischemic mitral regurgitation (IMR). Therefore, the objective of our study was to evaluate the clinical impact of mitral regurgitation (MR) recurrence and ventricular remodeling on long-term outcomes after SV-r combined with restrictive annuloplasty (RA-r).

METHODS

We performed a subanalysis of the papillary muscle approximation trial, studying 96 patients with severe IMR and coronary artery disease undergoing restrictive annuloplasty alongside subvalvular repair (SV-r + RA-r group) or restrictive annuloplasty alone (RA-r group). We analyzed treatment failure differences, the influence of residual MR, left ventricular remodeling, and clinical outcomes. The primary endpoint was treatment failure (composite of death; reoperation; or recurrence of moderate, moderate-to-severe, or severe MR) within 5 years of follow-up after the procedure.

RESULTS

A total of 45 patients showed failure of the treatment within 5 years, of which 16 patients underwent SV-r + RA-r (35.6%) and 29 underwent RA-r (64.4%, p = 0.006). Patients with significant residual MR presented with a higher rate of all-cause mortality at 5 years compared with trivial MR (HR 9.09, 95% CI 2.08-33.33, p = 0.003). MR progression occurred earlier in the RA-r group, as 20 patients in the RA-r group vs. 6 in SV-r + RA-r group had a significant MR 2 years after surgery (p = 0.002).

CONCLUSIONS

RA-r remains a surgical mitral repair technique with an increased risk of failure and mortality at 5 years compared with SV-r. The rates of recurrent MR are higher, and recurrence occurs earlier, with RA-r alone compared to SV-r. The addition of the subvalvular repair increases the durability of the repair, thus extending all of the benefits of preventing MR recurrence.

Description, Feasibility, and Histological Assessment of the Vsling, a Novel Transcatheter Ventricular Repair Device

Background

Reshaping the dilated left ventricle using a surgically implanted papillary muscle sling has been shown to provide long-term improvement in cardiac function compared to annuloplasty alone in patients with systolic heart failure. A papillary muscle sling which can be implanted via a transcatheter approach has the potential to make this treatment more widely available to patients.

Methods

The Vsling transcatheter papillary muscle sling device was evaluated in a chronic animal model (sacrificed at 30 and 90 days), in a simulator, and in a human cadaver.

Results

The Vsling device was successfully implanted in 10 pigs, 6 simulator procedures, and 1 human cadaver. Procedure complexity and device usability were rated as reasonable or better by 6 interventional cardiologists. Gross and histological analysis in chronic pigs through 90 days demonstrated near-complete endothelial coverage with mild inflammation and small hematoma formation but without adverse tissue reactions, thrombi, or embolization.

Conclusions

Preliminary feasibility and safety of the Vsling implant and implantation procedure have been demonstrated. Human trials are planned to begin in the summer of 2022.

Surgical mitral valve repair technique considerations based on the available evidence

Mitral valve regurgitation is the second most common valve disease in the western world. Surgery is currently the best tool for generating a long-lasting elimination of mitral valve regurgitation. However, the mitral valve apparatus is a complex anatomical and functional structure, and repair results and durability show substantial heterogeneity. This is not only due to differences in the underlying mitral valve regurgitation pathophysiology but also due to differences in repair techniques. Repair philosophies differ substantially from one surgeon to the other, and consensus for the technically best repair strategy has not been reached yet. We had previously addressed this topic by suggesting that ring sizing is "voodoo". We now review the available evidence regarding the various repair techniques described for structural and functional mitral valve regurgitation. Herein, we illustrate that for structural mitral valve regurgitation, resuspension of prolapsing valve segments or torn chordae with polytetrafluoroethylene sutures and annuloplasty can generate the most durable results paired with the best achievable hemodynamics. For functional mitral valve regurgitation, the evidence suggests that annuloplasty alone is insufficient in most cases to generate durable results, and additional subvalvular strategies are associated with improved durability and possibly improved clinical outcomes. This review addresses current strategies but also implausibilities in mitral valve repair and informs the mitral valve surgeon about the current evidence. We believe that this information may help improve outcomes in mitral valve repair as the heterogeneity of mitral valve regurgitation pathophysiology does not allow a one-size-fits-all concept.

Exploring the Operative Strategy for Secondary Mitral Regurgitation: A Systematic Review

Background

Mitral valve disease surgery is an evolving field with multiple possible interventions. There is an increasing body of evidence regarding the optimal strategy in secondary mitral regurgitation where the pathology lies within the ventricle. We conducted a systematic review to identify the benefits and limitations of each surgical option.

Methods

A systematic review of the literature was performed to identify pertinent randomized controlled trials (RCTs), propensity-matched observational series, and meta-analyses which were considered initially and followed by unmatched observational series using the MEDLINE, Ovid EMBASE, and Cochrane Library.

Results

We identified 6 different strategies for treating secondary mitral valve regurgitation: mitral valve replacement, restrictive mitral annuloplasty, surgical revascularization (with and without mitral annuloplasty), subvalvular procedures (papillary muscle approximation, papillary muscle relocation, ring and string procedure), and procedures directly targeting the mitral valve (edge-to-edge repair and anterior leaflet enlargement) alongside transcatheter heart valve therapy. We also highlighted the role of left ventricular assist devices in the management of this condition. The benefits and limitations of each intervention are highlighted.

Conclusion

There is currently no unanimous and shared strategy for the optimal treatment of patients with secondary IMR. The management of patients with secondary mitral regurgitation must be entrusted to a multidisciplinary Heart Team to ensure ideal intervention and patient matching for the best outcomes.

Surgical repair of ischemic mitral regurgitation: one ring does not fit all

PURPOSE OF REVIEW

The review summarizes the key parameters that can aid in determining the optimal treatment of ischemic mitral regurgitation (IMR).

RECENT FINDINGS

Left ventricular (LV) and mitral valve (MV) parameters are important for surgical planning and risk stratification in IMR. Although LV dimensions is one of the main parameters used in the guidelines, volumes more accurately depict LV remodelling. Furthermore, wall motion abnormalities and wall motion score index can also be useful for surgical planning in treatment of IMR. Viability is best measured with cardiac magnetic resonance, but it is not feasible in certain centres. In contrast, measurement of strain with echocardiography is an emerging and feasible tool for estimating viability. MV leaflet tethering and pattern measured with echocardiography are also useful for MV surgery. Anterior leaflet excursion angle can identify patients in whom undersized ring annuloplasty is potentially unsuitable.

SUMMARY

Treatment of IMR relies on accurate parameters that can determine the optimal surgical approach. In some patients, lack of viable myocardium suggests inadequacy of revascularization and thus, an adjunctive left ventricular reconstruction may be necessary. Degree and pattern of MV leaflet tethering can indicate whether ring annuloplasty, which is the most common repair technique, is sufficient or an adjunctive sub-valvular intervention is beneficial.

Ischemic functional mitral regurgitation: from pathophysiological concepts to current treatment options. A systemic review for optimal strategy

OBJECTIVE

The current treatment of ischemic functional mitral regurgitation (FMR) remains debated due to differences in inclusion criteria of randomized studies and baseline characteristics. Also, the role of left ventricular pathophysiology and the role of subvalvular apparatus have not been thoroughly investigated in recent literature.

METHODS

A literature search was performed from PubMed inception to June 2020.

RESULTS

Novel concepts of pathophysiology, such as the proportionate/disproportionate conceptual framework, the role of papillary muscles and left ventricular dysfunction, the impact of myocardial ischemia and revascularization, left ventricular remodeling, and the effect of restrictive annuloplasty or subvalvular procedures have been reviewed.

CONCLUSIONS

The clinical benefits associated with the use of MitraClip is more evident in patients with disproportionate FMR with greater and sustained left ventricular reverse remodeling. Importantly, in the absence of myocardial revascularization, expansion of myocardial scar tissue and non-perfused areas of ischemic myocardium occur with time, and this impact on outcomes with a longer follow-up period cannot be quantified. In advanced phases of FMR, neither mitral ring annuloplasty nor percutaneous therapies could significantly modify the established pathoanatomic alterations.

Standardized subannular repair for type IIIb functional mitral regurgitation in a minimally invasive mitral valve surgery setting†

OBJECTIVES

Subannular repair techniques in addition to undersized ring annuloplasty have been developed to address high mitral regurgitation (MR) recurrence rates after mitral valve repair in type IIIb MR. We compared the results of annuloplasty with simultaneous standardized subannular repair versus isolated annuloplasty, focusing on the periprocedural outcomes of minimally invasive procedures.

METHODS

A consecutive series of 108 patients with type IIIb functional MR with severe signs of bileaflet tethering underwent an annuloplasty + subannular repair (group A; n = 60) versus isolated annuloplasty (group B; n = 48). The primary end point of this prospective, parallel cohort study was death or recurrent MR >2, 1 year postoperatively. The secondary end points were survival and clinical outcomes, with special regard for the minimally invasively treated subgroups.

RESULTS

Duration of surgery, cardiopulmonary bypass time and aortic cross-clamp time were comparable between both study groups. Procedural outcomes as well as echocardiographic outcome parameters were similar and independent of access (fully endoscopic versus full sternotomy). At the 12-month follow-up, death or MR >2 occurred in 3.3% (2/60) of patients in group A vs in 20.8% (10/48) of patients in group B (P = 0.037). The overall mortality rate during the follow-up period was 1.7% (1/60) in group A vs 12.5% (6/48) in group B (P = 0.041).

CONCLUSIONS

Standardized realignment of papillary muscles is feasible and reproducible via a minimally invasive approach, resulting in excellent periprocedural outcomes, and has a clear potential to significantly decrease MR recurrence and improve 1-year outcomes compared to isolated annuloplasty.

Minimally invasive mitral valve repair for functional mitral regurgitation

Systolic heart failure is frequently accompanied by a relevant functional mitral valve regurgitation (FMR) which develops as a direct sequela of the ongoing left ventricular remodelling. The severity of mitral regurgitation is further aggravated by progressive left ventricular enlargement causing leaflet tethering and reduced systolic leaflet movement. The prognosis of such patients is obviously limited by an underlying left ventricular disease, and the correction of secondary FMR has been previously suggested as predominantly ‘cosmetic’ surgery in the setting of ongoing cardiomyopathy. Inferior results of an isolated annuloplasty in type IIIb FMR supported the philosophy of malignant course of progressive cardiomyopathy and resulted in increasingly restricted indications for mitral valve surgery for FMR in the guidelines. The lack of a standardized pathophysiological approach to correct type IIIb FMR led to the development of valve replacement strategy and edge-to-edge catheter-based mitral valve procedures, which became the most frequent procedures in the FMR setting in Europe. Modern mitral valve surgery combines the advantages of 3-dimensional endoscopic minimally invasive surgical approach with standardized subannular repair to address the pathophysiological background of type IIIb FMR. The perioperative results have been significantly improved, and there is a growing evidence of improved long-term stability of subannular repair procedures as compared to isolated annuloplasty. This review article aims to present the current state-of-the-art of the modern mitral valve surgery in FMR and provides suggestions for future trials analysing the potential advantages in these patients.

Diagnosis and Management of Ischemic Mitral Regurgitation: Evidence-Based Clinical Decision Making at the Point of Care

Anatomical, functional, and pathophysiologic mechanisms of ischemic mitral regurgitation (IMR) are markedly different from the primary mitral regurgitation. The older and ubiquitous cutoff of EROA (effective regurgitant orifice area) and Rvol (regurgitant volume) for IMR has been reinstated in the new guideline after a brief hiatus. There had always been a lack of good-quality evidence for its introduction for guiding IMR severity in the previous guideline, and we still do not have quality evidences that could justify its reintroduction. Unlike primary MR, IMR is usually associated with reduced ejection fraction. Therefore, it appears unrealistic to keep the similar cutoff for primary MR and IMR. The cutoff of severity can be modified according to projected values of Rvol normalized to ejection fraction and EROA normalized to Rvol. In addition, the treatment outcome in these patients is determined by factors (left ventricular dyssynchrony, annular dilatation, tenting area, tenting height, tenting volume, and myocardial viability) other than the simple grading. In this review article, a series of graph have been constructed from the numerical data derived from the literatures on IMR to depict the relationship between EROA, Rvol, left ventricular end diastolic volume, and ejection fraction in order to obtain a reasonable projection formula for EROA and Rvol. Furthermore, a management algorithm has been proposed for patients with IMR undergoing coronary artery bypass grafting based on echocardiographic predictors that influence the postoperative outcome.

Standardized Subannular Repair Improves Outcomes in Type IIIb Functional Mitral Regurgitation

BACKGROUND

The major drawback of isolated annuloplasty in secondary mitral regurgitation (MR) is the reoccurrence of MR. We prospectively compared the results of isolated annuloplasty vs annuloplasty with simultaneous standardized subannular repair.

METHODS

The study comprised 101 patients with secondary type IIIb MR. Of these, 51 underwent annuloplasty plus standardized subannular repair with realignment of both papillary muscles (subannular repair) and 50 underwent isolated annuloplasty. The primary study end point was the reoccurrence of MR >2 at the 1-year follow-up. Secondary end points were survival, freedom from major adverse cardiac events, and residual leaflet tethering.

RESULTS

Baseline characteristics were comparable in both groups. There was no significant difference in in-hospital mortality (P = .3). Although postrepair MR was comparable between the subannular repair and isolated annuloplasty subgroups, the residual leaflet tethering (tenting area, 127.6 ± 35.8 mm² vs 166.3 ± 47.3 mm², P = .02; posterior mitral leaflet angle, 19.2 ± 4.7 degrees vs 24.8 ± 5.2 degrees, P = .001; anterior mitral leaflet angle, 25.4 ± 5.8 degrees vs 34.1 ± 4.0 degrees, P = .001; and tenting height, 5.9 ± 1.4 mm vs 9.2 ± 2.2 mm, P = .001) were significantly increased in the isolated annuloplasty group (P < .001). At the 1-year follow-up, we found a significant difference between the groups in the freedom from MR >2 of 98% (50 of 51) for subannular repair vs 86.7% (39 of 45) for isolated annuloplasty (P = .045) and mortality of 0% (0 of 51) for subannular repair vs 10% (5 of 50) for isolated annuloplasty (P = .025).

CONCLUSIONS

In secondary MR with reduced leaflet motion, the combination of annuloplasty and standardized subannular repair is associated with a significantly reduced MR reoccurrence, decreased residual leaflet tenting, and significantly improved 1-year outcome compared with annuloplasty alone.

The unique mechanism of functional mitral regurgitation in acute myocardial infarction: a prospective dynamic 4D quantitative echocardiographic study

AIMS

Mechanisms of chronic ischaemic mitral regurgitation (IMR) are well-characterized by apically tethered leaflet caused by papillary muscles (PMs) displacement and adynamic mitral apparatus. We investigated the unique geometry and dynamics of the mitral apparatus in first acute myocardial infarction (MI) by using quantified 3D echocardiography.

METHODS AND RESULTS

We prospectively performed 3D echocardiography 2.3 ± 1.8 days after first MI, in 174 matched patients with (n = 87) and without IMR (n = 87). 3D echocardiography of left ventricular (LV) volumes and of mitral apparatus dynamics throughout cardiac cycle was quantified. Similar mitral quantification was obtained at chronic post-MI stage (n = 44). Mechanistically, acute IMR was associated with larger and flatter annulus (area 9.29 ± 1.74 cm2 vs. 8.57 ± 1.94 cm2, P = 0.002, saddle shape 12.7 ± 4.5% vs. 15.0 ± 4.6%, P = 0.001), and larger tenting (length 6.36 ± 1.78 mm vs. 5.60 ± 1.55 mm, P = 0.003) but vs. chronic MI, mitral apparatus displayed smaller alterations (all P < 0.01) and annular size, PM movement remained dynamic (all P < 0.01). Specific to acute IMR, without PM apical displacement (P > 0.70), greater separation (21.7 ± 4.9 mm vs. 20.0 ± 3.4 mm, P = 0.01), and widest angulation of PM (38.4 ± 6.2° for moderate vs. 33.5 ± 7.3° for mild vs. 31.4 ± 6.3° for no-IMR, P = 0.0009) wider vs. chronic MI (P < 0.01).

CONCLUSIONS

3D echocardiography of patients with first MI provides insights into unique 4D dynamics of the mitral apparatus in acute IMR. Mitral apparatus remained dynamic in acute MI and distinct IMR mechanism in acute MI is not PM displacement seen in chronic IMR but separation and excess angulation of PM deforming the mitral valve, probably because of sudden-onset regional wall motion abnormality without apparent global LV remodelling. This specific mechanism should be considered in novel therapeutic strategies for IMR complicating acute MI.

Mitral regurgitation: anatomy is destiny

Mitral regurgitation (MR) occurs when any of the valve and ventricular mitral apparatus components are disturbed. As MR progresses, left ventricular remodelling occurs, ultimately causing heart failure when the enlarging left ventricle (LV) loses its conical shape and becomes globular. Heart failure and lethal ventricular arrhythmias may develop if the left ventricular end-systolic volume index exceeds 55 ml/m2. These adverse changes persist despite satisfactory correction of the annular component of MR. Our goal was to describe this process and summarize evolving interventions that reduce the volume of the left ventricle and rebuild its elliptical shape. This 'valve/ventricle' approach addresses the spherical ventricular culprit and offsets the limits of treating MR by correcting only its annular component.

Mitral Valve and Subvalvular Repair for Secondary Mitral Regurgitation: Rationale and Clinical Outcomes of the Papillary Muscle Sling

Secondary mitral regurgitation (MR) is a common finding in patients with dilated cardiomyopathy, and it is associated with poor outcomes. It is the result of incomplete systolic closure of the mitral valve (MV) as a consequence of left ventricular dilatation, papillary muscle displacement with impaired systolic shortening, and mitral leaflet tethering. MV surgery may be performed in cases of significant secondary MR despite guideline-directed medical therapy. However, MV repair, which is most commonly performed with an undersized ring annuloplasty, is associated with a 30-60% recurrence of moderate or greater MR at mid-term follow-up. To improve MV repair durability, several adjunctive subvalvular procedures have been proposed, one of which is the addition of papillary muscle approximation utilizing a papillary muscle sling. Recent studies comparing the outcomes of a conventional undersized ring annuloplasty with a MV repair utilizing a papillary muscle sling have reported a significant reduction in recurrent moderate or severe MR, greater left ventricular reverse remodeling, and improved MV apparatus geometry with the addition of the papillary muscle sling. We present a comprehensive review of the pathophysiology of secondary MR, and the rationale and clinical outcomes of MV repair with papillary muscle sling placement for the treatment of secondary MR.

Subannular reconstruction in secondary mitral regurgitation: a meta-analysis

OBJECTIVE

Mitral valve repair using an undersized complete annuloplasty ring in secondary mitral regurgitation with restricted leaflet motion during systole (Carpentier's surgical classification of mitral valve pathology: type IIIb) only inadequately addresses the underlying left ventricular disease. This may lead to an ongoing ventricular remodelling and progressive papillary muscle displacement with increasing leaflet tethering. Several subannular techniques have been proposed to counteract the reoccurrence of mitral regurgitation after mitral valve repair. We aimed to evaluate the potential additive effect of such subannular techniques on the late reoccurrence rate of secondary mitral regurgitation.

METHODS

Systematic literature review and meta-analysis were performed on PubMed, Embase and Google Scholar for studies published up to March 2016 and reporting late reoccurrence of mitral regurgitation after mitral valve repair using standard annuloplasty (control group) versus annuloplasty with subannular correction (study group) cohorts. Primary endpoint was late reoccurrence of mitral regurgitation ≥2 after surgical mitral valve repair, as defined by follow-up echocardiography.

RESULTS

The cumulative number of 1093 patients in 12 included studies served as our study population. A total of 743 patients underwent combined mitral valve repair including annuloplasty and subannular manoeuvre (ie, study group), while the remaining 350 patients underwent an isolated ring annuloplasty (ie, control group). Secondary mitral regurgitation was caused by ischaemic heart disease in 733/743 patients in the study group and 334/350 patients in the control group. Mean echocardiographic follow-up was 42.7±13.9 months. Pooled outcome analysis demonstrated that the combination of subannular repair with ring annuloplasty was associated with a significantly lower reoccurrence rate of mitral regurgitation ≥2 as compared with annuloplasty alone (OR 0.27, 95% CI 0.19 to 0.38, P=0.0001).

CONCLUSION

The combination of subannular reconstruction and mitral valve annuloplasty is associated with a lower late reoccurrence of mitral regurgitation after surgical mitral valve repair, as compared with annuloplasty alone.

The role of papillary muscle approximation in mitral valve repair for the treatment of secondary mitral regurgitation

Secondary mitral regurgitation (MR) is present in up to half of patients with dilated cardiomyopathy, and is associated with a poor prognosis. It primarily results from progressive left ventricular remodelling, papillary muscle displacement and tethering of the mitral valve leaflets. Mitral valve repair with an undersized ring annuloplasty is the reparative procedure of choice in the treatment of secondary MR. However, this technique is associated with a 30-60% incidence of recurrent moderate or greater MR at mid-term follow-up, which results in progressive deterioration of left ventricular function and increased morbidity. Combined mitral valve repair and papillary muscle approximation has been applied in order to address both the annular and subvalvular dysfunction that coexist in secondary MR, which include graft and suture-based techniques. Herein, we provide a systematic review of the published literature regarding the technical aspects, clinical application, and outcomes of mitral valve repair with combined ring annuloplasty and papillary muscle approximation for the treatment of secondary MR.

Multimodality imaging assessment of mitral valve anatomy in planning for mitral valve repair in secondary mitral regurgitation

Secondary mitral regurgitation (MR) is frequent valvular heart disease and conveys worse prognostic. Therapeutic surgical or percutaneous options are available in the context of severe symptomatic secondary MR, but the best approach to treat these patients remains unclear, given the lack of clear clinical evidence of benefit. A comprehensive evaluation of the mitral valve apparatus and the left ventricle (LV) has the ability to clearly define and characterize the disease, and thus determine the best option for the patient to improve its clinical outcomes, as well as quality of life and symptoms. The current report reviews the mitral valve (MV) anatomy, the underlying mechanisms associated with secondary MR, the related therapeutic options available, and finally the usefulness of a multimodality imaging approach for the planning of surgical or percutaneous mitral valve intervention.

Are adjunct subvalvular techniques more effective than isolated restrictive annuloplasty for treating ischemic mitral regurgitation?

This review focused on whether subvalvular techniques are more effective than isolated restrictive annuloplasty in addressing ischemic mitral regurgitation (MR). Searching identified 445 papers and, following a selection process, we ended up with 10 articles. Two were propensity-matched studies, four retrospective and four prospective, non-randomized studies. The end points of interest were late recurrence of MR, other early echocardiographic outcomes of mitral function and early mortality. All studies focusing on echocardiographic measurements showed improved results in the groups where subvalvular repair techniques were used. In almost all studies, the recurrence of MR postoperatively was less when subvalvular techniques were used. No difference in early or in-hospital mortality was demonstrated in all four studies that included comparisons. We conclude that subvalvular techniques in combination with annuloplasty are safe and may better address ischemic MR than the use of annuloplasty ring alone.

Mitral valve repair

Mitral regurgitation (MR) is the most common valvular heart disease in the Western world. The MR can be either organic (mainly degenerative in Western countries) or functional (secondary to left ventricular remodeling in the context of ischemic or idiopathic dilated cardiomyopathy). Degenerative and functional MR are completely different disease entities that pose specific decision-making problems and require different management. The natural history of severe degenerative MR is clearly unfavorable. However, timely and effective correction of degenerative MR is associated with a normalization of life expectancy. By contrast, the prognostic impact of the correction of functional MR is still debated and controversial. In this review, we discuss the optimal treatment of both degenerative and functional MR, taking into account current surgical and percutaneous options. In addition, since a clear understanding of the etiology and mechanisms of valvular dysfunction is important to guide the timing and choice of treatment, the role of the heart team and of echo imaging in the management of MR is addressed as well.

Posterior Leaflet Detachment, Augmentation, and Reconstruction for Treatment of Functional Mitral Valve Regurgitation

Functional mitral regurgitation caused posterior leaflet tethering and central malcoaptation treated utilizing undersized annuloplasty alone is associated with high rates of early failure. We report the technical steps necessary for near complete near complete detachment, augmentation and reconstruction of a thin and diminutive posterior mitral leaflet to reproducibly re-establish normal mitral leaflet coaptation and eliminate functional MR.

Geometric perturbations in multiheaded papillary tip positions associated with acute ovine ischemic mitral regurgitation

BACKGROUND

Novel surgical approaches are focusing on the "ventricular disease" of ischemic mitral regurgitation (IMR), to correct altered papillary muscle (PM) tip positions (apical displacement) and ameliorate leaflet tethering. Due to the anatomic complexity of the subvalvular apparatus, however, the precise geometric perturbations of the multiheaded PM tips associated with IMR remain uncharacterized.

METHODS

In 6 adult sheep, we implanted 3 markers on each PM. To specifically identify distinct PM tips, 1 marker was placed on the PM origin of the dominant chord to the anterior, posterior, and commissural leaflets. Nine markers were placed on the edge of the posterior mitral leaflet, and 5 on the edge of the anterior mitral leaflet. Eight markers were sewn around the mitral annulus. Animals were studied immediately postoperatively, with biplane videofluoroscopy and transesophageal echocardiography, before and during acute snare occlusion of the proximal left circumflex coronary artery, to induce IMR. Papillary muscle tip and leaflet edge geometry was expressed as the orthogonal distance of each respective marker to the least-squares mitral annulus plane at end-systole. In addition, the distance from each PM tip marker to the mitral annulus "saddle horn" was calculated.

RESULTS

Acute left circumflex occlusion significantly increased mitral regurgitation from a baseline of 0.7 ± 0.3 to 2.5 ± 0.5 (P < .05). The IMR was associated with posterior leaflet restriction near the central leaflet edge, with simultaneous prolapse of both leaflets near the posterior commissure. No apical displacement of PM tips was observed during IMR, although the posterior PM moved farther away from the midseptal annulus.

CONCLUSIONS

During acute ischemia, no apical displacement of any PM tip was observed. Posterior PM movement away from the annular saddle horn, and toward the annulus, was associated with IMR and leaflet prolapse near the posterior commissure, and with restriction near the valve center. These data may help guide development of surgical interventions aimed at PM repositioning.

Surgical strategy for ischemic mitral regurgitation adopting subvalvular and ventricular procedures

PURPOSE

The progression of left ventricular (LV) remodeling and subsequent mitral valve tethering impair the results of reduction annuloplasty for ischemic mitral regurgitation (MR).

METHODS

We studied 90 patients who underwent surgical repair of ischemic MR between 1999 and 2013 according to our surgical strategy adding submitral and ventricular procedures to annuloplasty as follows: annuloplasty alone (stage 1, n = 30), additional papillary muscle approximation (PMA) for progression of tethering (stage 2, n = 26), and additional left ventriculoplasty with PMA for progression of LV remodeling and tethering (stage 3, n = 34).

RESULTS

The preoperative New York Heart Association (NYHA) functional classes (2.5 ± 0.7, 3.1 ± 0.7 and 3.3 ± 0.7 for stages 1, 2 and 3, respectively, P <0.001), LV end-diastolic diameters (56 ± 7 mm, 66 ± 5 mm and 70 ± 7 mm, P <0.001), and LV ejection fractions (45 ± 12%, 32 ± 9% and 27 ± 9%, P <0.001) significantly differed among the stages. In contrast, the MR grades did not significantly differ (2.9 ± 0.8, 3.0 ± 1.0, and 2.9 ± 1.1, respectively; P = 0.93). Both the rates of cardiac-related survival and freedom from reoperation were comparable among the 3 groups (log-rank P = 0.92 and 0.58, respectively).

CONCLUSION

Additional submitral and ventricular procedures can compensate for the possible impairment of the outcomes after annuloplasty alone for ischemic MR in patients with severe LV remodeling and tethering.

Predicting recurrent mitral regurgitation after mitral valve repair for severe ischemic mitral regurgitation

OBJECTIVES

The Cardiothoracic Surgical Trials Network recently reported no difference in the primary end point of left ventricular end-systolic volume index at 1 year postsurgery in patients randomized to repair (n = 126) or replacement (n = 125) for severe ischemic mitral regurgitation. However, patients undergoing repair experienced significantly more recurrent mitral regurgitation than patients undergoing replacement (32.6% vs 2.3%). We examined whether baseline echocardiographic and clinical characteristics could identify those who will develop moderate/severe recurrent mitral regurgitation or die.

METHODS

Our analysis includes 116 patients who were randomized to and received mitral valve repair. Logistic regression was used to estimate a model-based probability of recurrence or death from baseline factors. Receiver operating characteristic curves were constructed from these estimated probabilities to determine classification cut-points maximizing accuracy of prediction based on sensitivity and specificity.

RESULTS

Of the 116 patients, 6 received a replacement before leaving the operating room; all other patients had mild or less mitral regurgitation on intraoperative echocardiogram after repair. During the 2-year follow-up period, 76 patients developed moderate/severe mitral regurgitation or died (53 mitral regurgitation recurrences, 13 mitral regurgitation recurrences and death, and 10 deaths). The mechanism for recurrent mitral regurgitation was largely mitral valve leaflet tethering. Our model (including age, body mass index, sex, race, effective regurgitant orifice area, basal aneurysm/dyskinesis, New York Heart Association class, history of coronary artery bypass grafting, percutaneous coronary intervention, or ventricular arrhythmias) yielded an area under the receiver operating characteristic curve of 0.82.

CONCLUSIONS

The model demonstrated good discrimination in identifying patients who will survive 2 years without recurrent mitral regurgitation after mitral valve repair. Although our results require validation, they offer a clinically relevant risk score for selection of surgical candidates for this procedure.

Subvalvular techniques to optimize surgical repair of ischemic mitral regurgitation

PURPOSE OF REVIEW

Surgical treatment of ischemic mitral regurgitation with reduction annuloplasty is the current standard of practice, yet recurrence rates approaching 30% limit the benefits of repair in this subset of patients. In an effort to improve outcomes, attention has turned to understanding the contribution of leaflet tethering in this disease process. Subvalvular techniques to alleviate leaflet restriction have recently been incorporated into methods of repair.

RECENT FINDINGS

Parameters of left ventricular remodeling have been quantified as risk factors for recurrence of mitral regurgitation following reduction annuloplasty. Papillary muscle relocation restores the physiologic configuration of the subvalvular apparatus, and results in significantly reduced rates of recurrent mitral regurgitation and adverse cardiac events over time. Secondary chordal cutting or reimplantation results in significantly increased leaflet mobility, decreased severity of recurrent mitral regurgitation, and improved reverse remodeling without adverse effect on left ventricular function.

SUMMARY

A superior repair with decreased recurrence of mitral regurgitation and enhanced reversal of left ventricular remodeling is possible when subvalvular techniques are combined with traditional ring annuloplasty. Further understanding of preoperative parameters that predict disease recurrence and inclusion of concomitant subvalvular techniques in this subset of patients will be the next major advance in this field.

Benefits of submitral procedures for ischemic mitral regurgitation

The surgical strategy for ischemic mitral regurgitation (MR) remains controversial. Ischemic MR is a secondary valve disease caused by left ventricular (LV) remodeling and subsequent papillary muscle displacement, usually without structural valve lesions. Reduction annuloplasty is the standard surgical procedure for this condition, though it cannot clearly provide a survival benefit for those with LV dysfunction and is associated with a high prevalence of late recurrence of MR. The valvular procedure alone could be insufficient to treat ischemic MR in terms of long-term survival and the prevention of recurrence because ischemic MR is primarily a ventricular disorder. Thus, recent studies have focused on alternative procedures that target the primary cause of ischemic MR, the papillary muscles and left ventricle. We believe that the appropriate selection of surgical procedures among valvular, subvalvular, and even ventricular ones, considering the severity of LV remodeling for each patient would be more beneficial. Here we review recent studies featuring various surgical approaches to ischemic MR, especially with submitral procedures.

The extent of papillary muscle approximation affects mortality and durability of mitral valve repair for ischemic mitral regurgitation

Background

Since reduction annuloplasty alone for ischemic mitral regurgitation (MR) cannot prevent late recurrence of MR or improve survival for those with left ventricular (LV) dysfunction, and the surgical approach to this etiology is still controversial, we conducted a study to assess the efficacy of the additional papillary muscle approximation (PMA) procedure for ischemic MR by comparing the different subtypes of PMA.

Methods

We studied 45 patients who underwent mitral annuloplasty and papillary muscle approximation (PMA) for ischemic MR between 2003 and 2012. Papillary muscles were approximated entirely (cPMA: complete PMA, n = 32) through an LV incision or partially from the tips to mid-parts (iPMA: incomplete PMA, n = 13) through the mitral and aortic valves. Twenty-three patients with cPMA also underwent LV plasty (LVP). We assessed the outcomes after PMA by comparing cPMA and iPMA.

Results

The baseline MR grade, NYHA class, LV end-diastolic diameter, and LV ejection fraction (LVEF) were 2.8 ± 1.0, 3.2 ± 0.6, 67 ± 6 mm, and 30 ± 10%, respectively. There were no significant differences in these parameters among those with iPMA, cPMA/LVP-, and cPMA/LVP+, though iPMA patients had better LVEF than others. Three patients died before discharge and 12 died during the follow-up. Recurrence of grade 2+ and 3+ MR occurred in 8 and 2 patients, respectively. Reoperation for recurrent MR was performed only for the 2 patients with recurrence of grade 3+ MR. The cPMA was associated with lower mortality (log-rank P = 0.020) and a lower rate of recurrence of MR ≥2+ (log-rank P = 0.005) than iPMA. In contrast, there were no significant differences in the mortality (log-rank P = 0.45) and rate of recurrence (log-rank P = 0.98) between those with cPMA/LVP- and cPMA/LVP+. The 4-year survival rate and rate of freedom from recurrence of MR ≥2+ were 83% and 85% for those with cPMA, repectively. In contrast, the rates were 48% and 48% for those with iPMA, respectively.

Conclusions

Complete PMA could be associated with lower postoperative mortality and higher durability of mitral valve repair for ischemic MR.

Five-year real world outcomes of GeoForm ring implantation in patients with ischemic mitral regurgitation

BACKGROUND

Reductive ring annuloplasty represents the current standard surgical therapy for ischemic mitral regurgitation (IMR); however, the clinical results have been suboptimal. Etiology-specific prostheses such as the GeoForm annuloplasty ring have been designed to better address the annular and subvalvular perturbations associated with IMR. However, clinical experience is limited, and mid-term results are lacking.

METHODS

We reviewed the clinical outcomes of 86 patients who had undergone implantation of a GeoForm ring at our center from 2005 to 2011. Perioperative mortality and clinical parameters were derived from The Society of Thoracic Surgeons database. Follow-up survival was assessed using the Social Security Death Index. Surviving patients were interviewed by telephone for valve-specific follow-up data and to complete the Medical Outcomes Study, short-form, 36-item, quality-of-life questionnaire.

RESULTS

The mean grade of IMR preoperatively was 3.1±0.8 (range, 1-4+), 0.2±0.4 in the immediate postoperative period, and 0.7±0.7 at the last mean follow-up point of 41 months; only 2 patients developed ≥2+IMR during the follow-up period, for a 5-year freedom from recurrent 2+ IMR of 86%. The mean left ventricular end-diastolic and end-systolic diameters decreased from before to after surgery from 6.0±0.0 cm to 5.3±09 cm and 5.0±0.9 cm to 4.3±1.1 cm, respectively (P<.001). Perioperative mortality was 5.8% (5 of 86), and 1-, 3-, and 5-year survival was 87%, 81%, and 75%, respectively. At the last follow-up point, 80% of patients were in New York Heart Association class I and II, and their quality of life was equal to, or better than, age-matched controls from the general population.

CONCLUSIONS

Implantation of the GeoForm ring offers very good control of IMR, with low rate of recurrent IMR at mid-term follow-up. The use of this prosthesis was associated with good perioperative mortality, mid-term survival, and quality of life.

Surgical technique: papillary muscle sling for functional mitral regurgitation during minimally invasive valve surgery

In patients with functional mitral regurgitation, the placement of a sling encircling both papillary muscles in conjunction with mitral annuloplasty appears to be a rational approach for surgical correction, because it addresses both the mitral valve and the deformities of the subvalvular mitral apparatus. Reports in the literature that describe the utilization of this technique are few, and mainly involve a median sternotomy approach. The purpose of this communication is to describe the technical details of performing this procedure via a minimally invasive approach.

Surgical management of ischemic mitral regurgitation: indications, procedures, and future prospects

Ischemic mitral regurgitation (IMR) is one of the most important risk factors affecting prognosis of patients who suffer from myocardial infarction. The mechanisms of IMR, the indications for surgical intervention, the operative procedures, and the limitations of surgical procedures are discussed in this review article.

Surgical ventricular restoration for the treatment of heart failure

Heart failure (HF) is an emerging epidemic affecting 15 million people in the USA and Europe. HF-related mortality was unchanged between 1995 and 2009, despite a decrease in the incidence of cardiovascular disease. Conventional explanations include an aging population and improved treatment of acute myocardial infarction and HF. An adverse relationship between structure and function is the central theme in patients with systolic dysfunction. The normal elliptical ventricular shape becomes spherical in ischemic, valvular, and nonischemic dilated cardiomyopathy. Therapeutic decisions should be made on the basis of ventricular volume rather than ejection fraction. When left ventricular end-systolic volume index exceeds 60 ml/m², medical therapy, CABG surgery, and mitral repair have limited benefit. This form-function relationship can be corrected by surgical ventricular restoration (SVR), which returns the ventricle to a normal volume and shape. Consistent early and late benefits in the treatment of ischemic dilated cardiomyopathy with SVR have been reported in >5,000 patients from various international centers. The prospective, randomized STICH trial did not confirm these findings and the reasons for this discrepancy are examined in detail. Future surgical options for SVR in nonischemic and valvular dilated cardiomyopathy, and its integration with left ventricular assist devices and cell therapy, are described.